#include<bits/stdc++.h>
using namespace std;

const int N = 200003,null = 0x3f3f3f3f;
int h[N];


int find(int x)
{
    int k = (x%N+N)%N;
    
    while(h[k]!=null && h[k]!=x)
    {
        k++;
        if(k==N) k=0;
    }
   return k;
}
int main()
{
    int n;
    cin>>n;
    
    memset(h,0x3f,sizeof h);
    
    while(n--)
    {
        char op[2];
        int x;
        cin>>op>>x;
        int k = find(x);
        if(*op=='I') h[k] = x;
        else{
            if(h[k]!=null) puts("Yes");
            else puts("No");
        }
    }
    
    return 0;
}